v01

thirdparty/basalt-headers/test/benchmark/src/benchmark_runner.cc

@@ -0,0 +1,348 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "benchmark_runner.h"
+
+#include "benchmark/benchmark.h"
+#include "benchmark_api_internal.h"
+#include "internal_macros.h"
+
+#ifndef BENCHMARK_OS_WINDOWS
+#ifndef BENCHMARK_OS_FUCHSIA
+#include <sys/resource.h>
+#endif
+#include <sys/time.h>
+#include <unistd.h>
+#endif
+
+#include <algorithm>
+#include <atomic>
+#include <condition_variable>
+#include <cstdio>
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <thread>
+#include <utility>
+
+#include "check.h"
+#include "colorprint.h"
+#include "commandlineflags.h"
+#include "complexity.h"
+#include "counter.h"
+#include "internal_macros.h"
+#include "log.h"
+#include "mutex.h"
+#include "perf_counters.h"
+#include "re.h"
+#include "statistics.h"
+#include "string_util.h"
+#include "thread_manager.h"
+#include "thread_timer.h"
+
+namespace benchmark {
+
+namespace internal {
+
+MemoryManager* memory_manager = nullptr;
+
+namespace {
+
+static constexpr IterationCount kMaxIterations = 1000000000;
+
+BenchmarkReporter::Run CreateRunReport(
+    const benchmark::internal::BenchmarkInstance& b,
+    const internal::ThreadManager::Result& results,
+    IterationCount memory_iterations,
+    const MemoryManager::Result& memory_result, double seconds,
+    int64_t repetition_index, int64_t repeats) {
+  // Create report about this benchmark run.
+  BenchmarkReporter::Run report;
+
+  report.run_name = b.name();
+  report.family_index = b.family_index();
+  report.per_family_instance_index = b.per_family_instance_index();
+  report.error_occurred = results.has_error_;
+  report.error_message = results.error_message_;
+  report.report_label = results.report_label_;
+  // This is the total iterations across all threads.
+  report.iterations = results.iterations;
+  report.time_unit = b.time_unit();
+  report.threads = b.threads();
+  report.repetition_index = repetition_index;
+  report.repetitions = repeats;
+
+  if (!report.error_occurred) {
+    if (b.use_manual_time()) {
+      report.real_accumulated_time = results.manual_time_used;
+    } else {
+      report.real_accumulated_time = results.real_time_used;
+    }
+    report.cpu_accumulated_time = results.cpu_time_used;
+    report.complexity_n = results.complexity_n;
+    report.complexity = b.complexity();
+    report.complexity_lambda = b.complexity_lambda();
+    report.statistics = &b.statistics();
+    report.counters = results.counters;
+
+    if (memory_iterations > 0) {
+      report.has_memory_result = true;
+      report.allocs_per_iter =
+          memory_iterations ? static_cast<double>(memory_result.num_allocs) /
+                                  memory_iterations
+                            : 0;
+      report.max_bytes_used = memory_result.max_bytes_used;
+    }
+
+    internal::Finish(&report.counters, results.iterations, seconds,
+                     b.threads());
+  }
+  return report;
+}
+
+// Execute one thread of benchmark b for the specified number of iterations.
+// Adds the stats collected for the thread into manager->results.
+void RunInThread(const BenchmarkInstance* b, IterationCount iters,
+                 int thread_id, ThreadManager* manager,
+                 PerfCountersMeasurement* perf_counters_measurement) {
+  internal::ThreadTimer timer(
+      b->measure_process_cpu_time()
+          ? internal::ThreadTimer::CreateProcessCpuTime()
+          : internal::ThreadTimer::Create());
+  State st =
+      b->Run(iters, thread_id, &timer, manager, perf_counters_measurement);
+  BM_CHECK(st.error_occurred() || st.iterations() >= st.max_iterations)
+      << "Benchmark returned before State::KeepRunning() returned false!";
+  {
+    MutexLock l(manager->GetBenchmarkMutex());
+    internal::ThreadManager::Result& results = manager->results;
+    results.iterations += st.iterations();
+    results.cpu_time_used += timer.cpu_time_used();
+    results.real_time_used += timer.real_time_used();
+    results.manual_time_used += timer.manual_time_used();
+    results.complexity_n += st.complexity_length_n();
+    internal::Increment(&results.counters, st.counters);
+  }
+  manager->NotifyThreadComplete();
+}
+
+}  // end namespace
+
+BenchmarkRunner::BenchmarkRunner(
+    const benchmark::internal::BenchmarkInstance& b_,
+    BenchmarkReporter::PerFamilyRunReports* reports_for_family_)
+    : b(b_),
+      reports_for_family(reports_for_family_),
+      min_time(!IsZero(b.min_time()) ? b.min_time() : FLAGS_benchmark_min_time),
+      repeats(b.repetitions() != 0 ? b.repetitions()
+                                   : FLAGS_benchmark_repetitions),
+      has_explicit_iteration_count(b.iterations() != 0),
+      pool(b.threads() - 1),
+      iters(has_explicit_iteration_count ? b.iterations() : 1),
+      perf_counters_measurement(
+          PerfCounters::Create(StrSplit(FLAGS_benchmark_perf_counters, ','))),
+      perf_counters_measurement_ptr(perf_counters_measurement.IsValid()
+                                        ? &perf_counters_measurement
+                                        : nullptr) {
+  run_results.display_report_aggregates_only =
+      (FLAGS_benchmark_report_aggregates_only ||
+       FLAGS_benchmark_display_aggregates_only);
+  run_results.file_report_aggregates_only =
+      FLAGS_benchmark_report_aggregates_only;
+  if (b.aggregation_report_mode() != internal::ARM_Unspecified) {
+    run_results.display_report_aggregates_only =
+        (b.aggregation_report_mode() &
+         internal::ARM_DisplayReportAggregatesOnly);
+    run_results.file_report_aggregates_only =
+        (b.aggregation_report_mode() & internal::ARM_FileReportAggregatesOnly);
+    BM_CHECK(FLAGS_benchmark_perf_counters.empty() ||
+             perf_counters_measurement.IsValid())
+        << "Perf counters were requested but could not be set up.";
+  }
+}
+
+BenchmarkRunner::IterationResults BenchmarkRunner::DoNIterations() {
+  BM_VLOG(2) << "Running " << b.name().str() << " for " << iters << "\n";
+
+  std::unique_ptr<internal::ThreadManager> manager;
+  manager.reset(new internal::ThreadManager(b.threads()));
+
+  // Run all but one thread in separate threads
+  for (std::size_t ti = 0; ti < pool.size(); ++ti) {
+    pool[ti] = std::thread(&RunInThread, &b, iters, static_cast<int>(ti + 1),
+                           manager.get(), perf_counters_measurement_ptr);
+  }
+  // And run one thread here directly.
+  // (If we were asked to run just one thread, we don't create new threads.)
+  // Yes, we need to do this here *after* we start the separate threads.
+  RunInThread(&b, iters, 0, manager.get(), perf_counters_measurement_ptr);
+
+  // The main thread has finished. Now let's wait for the other threads.
+  manager->WaitForAllThreads();
+  for (std::thread& thread : pool) thread.join();
+
+  IterationResults i;
+  // Acquire the measurements/counters from the manager, UNDER THE LOCK!
+  {
+    MutexLock l(manager->GetBenchmarkMutex());
+    i.results = manager->results;
+  }
+
+  // And get rid of the manager.
+  manager.reset();
+
+  // Adjust real/manual time stats since they were reported per thread.
+  i.results.real_time_used /= b.threads();
+  i.results.manual_time_used /= b.threads();
+  // If we were measuring whole-process CPU usage, adjust the CPU time too.
+  if (b.measure_process_cpu_time()) i.results.cpu_time_used /= b.threads();
+
+  BM_VLOG(2) << "Ran in " << i.results.cpu_time_used << "/"
+             << i.results.real_time_used << "\n";
+
+  // By using KeepRunningBatch a benchmark can iterate more times than
+  // requested, so take the iteration count from i.results.
+  i.iters = i.results.iterations / b.threads();
+
+  // Base decisions off of real time if requested by this benchmark.
+  i.seconds = i.results.cpu_time_used;
+  if (b.use_manual_time()) {
+    i.seconds = i.results.manual_time_used;
+  } else if (b.use_real_time()) {
+    i.seconds = i.results.real_time_used;
+  }
+
+  return i;
+}
+
+IterationCount BenchmarkRunner::PredictNumItersNeeded(
+    const IterationResults& i) const {
+  // See how much iterations should be increased by.
+  // Note: Avoid division by zero with max(seconds, 1ns).
+  double multiplier = min_time * 1.4 / std::max(i.seconds, 1e-9);
+  // If our last run was at least 10% of FLAGS_benchmark_min_time then we
+  // use the multiplier directly.
+  // Otherwise we use at most 10 times expansion.
+  // NOTE: When the last run was at least 10% of the min time the max
+  // expansion should be 14x.
+  bool is_significant = (i.seconds / min_time) > 0.1;
+  multiplier = is_significant ? multiplier : 10.0;
+
+  // So what seems to be the sufficiently-large iteration count? Round up.
+  const IterationCount max_next_iters = static_cast<IterationCount>(
+      std::lround(std::max(multiplier * static_cast<double>(i.iters),
+                           static_cast<double>(i.iters) + 1.0)));
+  // But we do have *some* sanity limits though..
+  const IterationCount next_iters = std::min(max_next_iters, kMaxIterations);
+
+  BM_VLOG(3) << "Next iters: " << next_iters << ", " << multiplier << "\n";
+  return next_iters;  // round up before conversion to integer.
+}
+
+bool BenchmarkRunner::ShouldReportIterationResults(
+    const IterationResults& i) const {
+  // Determine if this run should be reported;
+  // Either it has run for a sufficient amount of time
+  // or because an error was reported.
+  return i.results.has_error_ ||
+         i.iters >= kMaxIterations ||  // Too many iterations already.
+         i.seconds >= min_time ||      // The elapsed time is large enough.
+         // CPU time is specified but the elapsed real time greatly exceeds
+         // the minimum time.
+         // Note that user provided timers are except from this sanity check.
+         ((i.results.real_time_used >= 5 * min_time) && !b.use_manual_time());
+}
+
+void BenchmarkRunner::DoOneRepetition() {
+  assert(HasRepeatsRemaining() && "Already done all repetitions?");
+
+  const bool is_the_first_repetition = num_repetitions_done == 0;
+  IterationResults i;
+
+  // We *may* be gradually increasing the length (iteration count)
+  // of the benchmark until we decide the results are significant.
+  // And once we do, we report those last results and exit.
+  // Please do note that the if there are repetitions, the iteration count
+  // is *only* calculated for the *first* repetition, and other repetitions
+  // simply use that precomputed iteration count.
+  for (;;) {
+    i = DoNIterations();
+
+    // Do we consider the results to be significant?
+    // If we are doing repetitions, and the first repetition was already done,
+    // it has calculated the correct iteration time, so we have run that very
+    // iteration count just now. No need to calculate anything. Just report.
+    // Else, the normal rules apply.
+    const bool results_are_significant = !is_the_first_repetition ||
+                                         has_explicit_iteration_count ||
+                                         ShouldReportIterationResults(i);
+
+    if (results_are_significant) break;  // Good, let's report them!
+
+    // Nope, bad iteration. Let's re-estimate the hopefully-sufficient
+    // iteration count, and run the benchmark again...
+
+    iters = PredictNumItersNeeded(i);
+    assert(iters > i.iters &&
+           "if we did more iterations than we want to do the next time, "
+           "then we should have accepted the current iteration run.");
+  }
+
+  // Oh, one last thing, we need to also produce the 'memory measurements'..
+  MemoryManager::Result memory_result;
+  IterationCount memory_iterations = 0;
+  if (memory_manager != nullptr) {
+    // Only run a few iterations to reduce the impact of one-time
+    // allocations in benchmarks that are not properly managed.
+    memory_iterations = std::min<IterationCount>(16, iters);
+    memory_manager->Start();
+    std::unique_ptr<internal::ThreadManager> manager;
+    manager.reset(new internal::ThreadManager(1));
+    RunInThread(&b, memory_iterations, 0, manager.get(),
+                perf_counters_measurement_ptr);
+    manager->WaitForAllThreads();
+    manager.reset();
+
+    memory_manager->Stop(&memory_result);
+  }
+
+  // Ok, now actually report.
+  BenchmarkReporter::Run report =
+      CreateRunReport(b, i.results, memory_iterations, memory_result, i.seconds,
+                      num_repetitions_done, repeats);
+
+  if (reports_for_family) {
+    ++reports_for_family->num_runs_done;
+    if (!report.error_occurred) reports_for_family->Runs.push_back(report);
+  }
+
+  run_results.non_aggregates.push_back(report);
+
+  ++num_repetitions_done;
+}
+
+RunResults&& BenchmarkRunner::GetResults() {
+  assert(!HasRepeatsRemaining() && "Did not run all repetitions yet?");
+
+  // Calculate additional statistics over the repetitions of this instance.
+  run_results.aggregates_only = ComputeStats(run_results.non_aggregates);
+
+  return std::move(run_results);
+}
+
+}  // end namespace internal
+
+}  // end namespace benchmark